J/A+A/558/A60 CO(2-1) observations of central AGN at z=1.4 (Casasola+, 2013)
A gas-rich AGN near the centre of a galaxy cluster at z ∼ 1.4.
Casasola V., Magrini L., Combes F., Mignano A., Sani E., Paladino R.,
Fontani F.
<Astron. Astrophys. 558, A60 (2013)>
=2013A&A...558A..60C 2013A&A...558A..60C
ADC_Keywords: Clusters, galaxy ; Active gal. nuclei ; Carbon monoxide ;
Interferometry
Keywords: galaxies: active - galaxies: individual: AGN 1317 -
galaxies: clusters: individual: 7C 1756+6520 -
galaxies: distances and redshifts - galaxies: high-redshift -
galaxies: ISM
Abstract:
The formation of the first virialized structures in overdensities
dates back to ∼9Gyr ago, i.e. in the redshift range z∼1.4-1.6.
Some models of structure formation predict that the star formation
activity in clusters was high at that epoch, implying large reservoirs
of cold molecular gas. Aiming at finding a trace of this expected high
molecular gas content in primeval clusters, we searched for the
12CO(2-1) line emission in the most luminous active galactic nucleus
(AGN) of the cluster around the radio galaxy 7C 1756+6520 at z∼1.4,
one of the farthest spectroscopic confirmed clusters. This AGN, called
AGN.1317, is located in the neighbourhood of the central radio galaxy
at a projected distance of ∼780 kpc. The IRAM Plateau de Bure
Interferometer was used to investigate the molecular gas quantity in
AGN.1317, observing the 12CO(2-1) emission line. We detect CO
emission in an AGN belonging to a galaxy cluster at z∼1.4. We measured
a molecular gas mass of 1.1x1010M☉, comparable to that found
in submillimeter galaxies. In optical images, AGN.1317 does not seem
to be part of a galaxy interaction or merger. We also derived the
nearly instantaneous star formation rate (SFR) from Halpha flux
obtaining a SFR∼65M☉/yr. This suggests that AGN.1317 is actively
forming stars and will exhaust its reservoir of cold gas in
∼0.2-1.0Gyr.
Description:
12CO(2-1) intensity map obtained with the IRAM PdBI toward AGN.1317.
Objects:
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RA (2000) DE Designation(s)
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17 56 55.75 +65 19 07.0 AGN.1317 = [GSS2010] AGN.1317
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
co21.fits 512 9744 *CO(2-1) line (95.4 GHz) (in GILDAS-IMAGE)
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Note on co21.fits: Scale: 02.arcsec/pix. Vlsr range: [-171, 193]km/s.
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Acknowledgements:
Viviana Casasola, casasola(at)ira.inaf.it
(End) V. Casasola [INAF-IRA & IT-ARC, Italy], P. Vannier [CDS] 20-Sep-2013